Piperazine sultosylate appears specifically described in Certificate of Addition No. 477,098 (Lab. del Dr. Esteve, S. A.) of Spanish Patent No. 414,366 (Lab. del Dr. Esteve, S. A.). The product is obtained from the pyridine salt of formula II ##STR2## which in its turn has been obtained by tosylation in a pyridine medium of the diethylamine salt of 2,5-dihydroxybenzenesulphonic acid, of formula III, also known as ethamsylate. ##STR3##
The same process is described in identical terms in the American patents U.S. Pat. No. 3,954,767 and U.S. Pat. No. 4,115,648, also in the name of Lab. del Dr. Esteve, S. A.
This process enables the desired product to be obtained, but has considerable disadvantages for its industrial application.
In the first place, the use of pyridine as a reaction medium always has significant drawbacks, such as its toxicity, high cost and difficulty of recovery.
Moreover, it is difficult to displace the pyridine completely from the salt of formula II to obtain a piperazine sultosylate of the purity required for its use in a pharmaceutical speciality.